Systems and methods including lead and electrode structures sized and configured for implantation in adipose tissue

ABSTRACT

A stimulation electrode assembly comprises an elongated lead sized and configured to be implanted within an adipose tissue region. The lead includes an electrically conductive portion to apply electrical stimulation to nerve or muscle in the adipose tissue region and at least one expandable anchoring structure deployable from the lead to engage adipose tissue and resist dislodgment and/or migration of the electrically conductive portion within the adipose tissue region.

RELATED APPLICATIONS

This application is a continuation application of co-pending U.S. patentapplication Ser. No. 11/150,419, filed Jun. 10, 2005, and entitled“Method for Affecting Urinary Function with Electrode Implantation inAdipose Tissue,” which claims the benefit of U.S. Provisional PatentApplication Ser. No. 60/578,742, filed Jun. 10, 2004, and entitled“Systems and Methods for Bilateral Stimulation of Left and RightBranches of the Dorsal Genital Nerves to Treat Dysfunctions, Such asUrinary Incontinence.”

This application is also a continuation-in-part of co-pending U.S.patent application Ser. No. 11/545,339, filed Nov. 10, 2006, andentitled “Portable Percutaneous Assemblies, Systems, and Methods forProviding Highly Selective Functional or Therapeutic NeuromuscularStimulation,” which is a continuation application of U.S. patentapplication Ser. No. 10/777,771, filed Feb. 12, 2004, (now U.S. Pat. No.7,120,499), and entitled “Portable Percutaneous Assemblies, Systems, andMethods for Providing Highly Selective Functional or TherapeuticNeurostimulation.” Each of the preceding applications is incorporatedherein by reference.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH

This invention was made with government support under grant numbers1R43AG021851-01 awarded by the National Institutes of Health, throughthe National Institute of Aging, and 1R43AG022292-01 awarded by theNational Institutes of Health, through the National Institute of Aging.The Government has certain rights in the invention.

FIELD OF THE INVENTION

This invention relates to systems and methods for stimulating nerves andmuscles in animals, including humans.

BACKGROUND OF THE INVENTION

Thirteen million Americans suffer from various types of urinaryincontinence.

The most prevalent type of urinary incontinence (22% of the total) iscalled Stress Incontinence (SUI). SUI is characterized by the unintendedemission of urine during everyday activities and events, such aslaughing, coughing, sneezing, exercising, or lifting. These activitiesand events cause an increase in bladder pressure resulting in loss ofurine due to inadequate contraction of the sphincter muscle around theoutlet of the bladder.

Another prevalent type of urinary incontinence (18% of the total) iscalled Urinary Urge Incontinence (UUI). UUI is characterized by a strongdesire to urinate, followed by involuntary contractions of the bladder.Because the bladder actually contracts, urine is released quickly,making it impossible for urge incontinence sufferers to predict when theproblem will occur. UUI can be caused by infections, sphincterdisorders, or nervous system disorders that affect the bladder.

Many people (47% of the total) encounter a combination of bladdercontrol disorders.

Damage to the bladder, urethra, periurethral muscles and sphincters,nerves, and accessory organs can be experienced by women duringchildbirth or hysterectomy. This damage can lead to urinaryincontinence. Prostate problems can lead to urinary incontinence in men.The number of people suffering from urinary incontinence is on the riseas the population ages.

Various treatment modalities for urinary incontinence have beendeveloped. These modalities typically involve drugs, surgery, or both.Disposable pads can also used, not to treat the disorder, but to dealwith its consequences.

Pharmocotherapy (with and without attendant behavioral therapy) appearsto moderate the incidence of urinary incontinence episodes, but noteliminate them. Drug therapy alone can lead to a reduction ofincontinence episodes after eight weeks by about 73%. When combined withbehavioral therapy, the reduction after eight weeks is about 84% (Burgioet al, JAGS. 2000; 48:370-374). However, others have questioned theclinical significance of the results, noting that the differences inoutcomes using anticholinergic drugs and placebo were small, apart fromthe increased rate of dry mouth in patients receiving active treatment(Herbison P, Hay-Smith J, Ellis J, Moore K, BMJ 2003; 326:841).

One present surgical modality involves the posterior installation by apercutaneous needle of electrodes through the muscles and ligaments overthe S3 spinal foramen near the right or left sacral nerve roots(InterStim™ Treatment, Medtronic). The electrodes are connected to aremote neurostimulator implantable pulse generator implanted in asubcutaneous pocket on the right hip to provide unilateral spinal nervestimulation. This surgical procedure near the spine is complex andrequires the skills of specialized medical personnel. Furthermore, interms of outcomes, the modality has demonstrated limited effectiveness.For people suffering from UUI, less than 50% have remained dry followingthe surgical procedure. In terms of frequency of incontinence episodes,less than 67% of people undergoing the surgical procedure reduced thenumber of voids by greater than 50%, and less than 69% reduced thenumber of voids to normal levels (4 to 7 per day). This modality hasalso demonstrated limited reliability. Fifty-two percent (52%) of peopleundergoing this surgical procedure have experienced therapy-relatedadverse events, and of these 54% required hospitalization or surgery toresolve the issue. Many (33%) require surgical revisions.

It has been reported that 64% of people undergoing some form oftreatment for urinary incontinence are not satisfied with their currenttreatment modality (National Association for Incontinence, 1988).

A recently proposed alternative surgical modality (Advanced BionicsCorporation) entails the implantation through a 12 gauge hypodermicneedle of an integrated neurostimulator and bi-polar electrode 16assembly (called the Bion® System) through the perineum into tissue nearthe pudendal nerve on the left side adjacent the ischial spine. See,e.g., Mann et al, Published Patent Application US2002/0055761. Theclinical effectiveness of this modality is not known.

There remains a need for systems and methods that can restore urinarycontinence, in a straightforward manner, without requiring drug therapyand complicated surgical procedures.

SUMMARY OF THE INVENTION

The invention provides improved assemblies, systems, and methods usedfor stimulating nerves and muscles in animals, including humans.

One aspect of the invention provides assemblies, systems, and methodsincluding a stimulation electrode assembly. The electrode assemblyincludes an elongated lead sized and configured to be implanted inadipose tissue at or near a pubic symphysis. The lead includes at leastone electrode to apply electrical stimulation to a nerve in the adiposetissue, the nerve affecting urinary function, and at least oneexpandable anchoring structure deployable from the lead to engage theadipose tissue and resist dislodgment and/or migration of the lead andelectrode within the adipose tissue, the expandable anchoring structuresized and configured to form an open structure that enlarges in diameterfrom distal to proximal to resist proximal passage of the lead andelectrode through the adipose tissue. The nerve may include a leftand/or right branch of the dorsal genital nerve.

Another aspect of the invention provides assemblies, systems, andmethods including a system to affect urinary function. The systemincludes a stimulation electrode assembly, the assembly comprising anelongated lead, the lead including an electrically conductive portionand at least one expandable anchoring structure deployable from thelead. The electrically conductive portion and the at least oneexpandable anchoring structure are sized and configured to be implantedin an adipose tissue region at or near a pubic symphysis innervated by anerve affecting urinary function.

The electrically conductive portion is sized and configured to applyelectrical stimulation to the nerve in the adipose tissue regionaffecting urinary function, and the expandable anchoring structure issized and configured to engage the adipose tissue and resist dislodgmentand/or migration of the electrically conductive portion within theadipose tissue region.

An implantable pulse generator may be included and is sized andconfigured to be implanted in subcutaneous tissue in an anterior pelvicregion remote from the at least one electrically conductive portion, andto convey electrical stimulation waveforms to the stimulation electrodeassembly to affect urinary function.

Yet another aspect of the invention provides assemblies, systems, andmethods including a kit of components. The kit may come in many forms,and may include a stimulation electrode assembly, the assemblycomprising an elongated lead sized and configured to be implanted in anadipose tissue region at or near a pubic symphysis, the lead includingat least one electrode to apply electrical stimulation to a nerve in theadipose tissue region, the nerve affecting urinary function, and atleast one expandable anchoring structure deployable from the lead toengage the adipose tissue and resist dislodgment and/or migration of thelead and electrode within the adipose tissue region, the expandableanchoring structure sized and configured to form an open structure thatenlarges in diameter from distal to proximal to resist proximal passageof the lead and electrode through the adipose tissue region

The kits may also include instructions for implanting the electrode andexpandable anchoring structure in the adipose tissue region at or nearthe pubic symphysis, and deploying the expandable anchoring structure inthe adipose tissue region to resist dislodgment and/or migration of thelead and electrode within the adipose tissue.

Another aspect of the kit further includes a pulse generator to conveyelectrical stimulation waveforms to the stimulation electrode, andinstructions for coupling the stimulation electrode assembly to thepulse generator, and operating the pulse generator to convey electricalstimulation waveforms to the stimulation electrode assembly to achievestimulation of the nerve affecting urinary function. The instructionsmay include implanting the pulse generator in subcutaneous tissue in ananterior pelvic region remote from the at least one electrode.

Another aspect of the invention provides assemblies, systems, andmethods including a method of stimulating a nerve to affect urinaryfunction. The method may include providing a stimulation electrodeassembly, the assembly comprising an elongated lead sized and configuredto be implanted in adipose tissue at or near a pubic symphysis, the leadincluding at least one electrode to apply electrical stimulation to anerve in the adipose tissue, the nerve affecting urinary function, andat least one expandable anchoring structure deployable from the lead toengage the adipose tissue and resist dislodgment and/or migration of thelead and electrode within the adipose tissue, the expandable anchoringstructure sized and configured to form an open structure that enlargesin diameter from distal to proximal to resist proximal passage of thelead and electrode through the adipose tissue.

The method may further include placing the expandable anchoringstructure in a collapsed condition, implanting the electricallyconductive portion and the expandable anchoring structure in the adiposetissue, expanding the anchoring structure into the adipose tissue toresist dislodgment and/or migration of the electrically conductiveportion within the adipose tissue, tunneling a proximal portion of thestimulation electrode assembly to an anterior pelvic region remote fromthe at least one electrode, providing an implantable pulse generatorsized and configured to be positioned in subcutaneous tissue in theanterior pelvic region remote from the at least one electrode, couplingthe implantable pulse generators to the stimulation electrode assembly,implanting the implantable pulse generator in the anterior pelvic regionremote from the at least one electrode, and operating the implantablepulse generator to convey electrical stimulation waveforms through thestimulation electrode assembly to achieve selective stimulation of thenerve to affect urinary function.

Yet another aspect of the invention provides assemblies, systems, andmethods including a system to affect urinary function. The systemcomprises a stimulation electrode assembly, the assembly comprising anelongated lead, the lead including an electrically conductive portion.The electrically conductive portion is sized and configured to beimplanted in an adipose tissue region at or near a pubic symphysisinnervated by a nerve affecting urinary function, and to applyelectrical stimulation to the nerve in the adipose tissue regionaffecting urinary function.

The system includes an external pulse generator sized and configured tobe worn by a patient, the external pulse generator comprising aremovable and replaceable electronics pod, the electronics podcomprising circuitry adapted to generate electrical stimulation currentpatterns to be delivered through the lead and to the electricallyconductive portion, the electronics pod also comprising a power inputbay adapted to receive a disposable power source that can be releasedand replaced for a prescription period, and instructions for useprescribing the release and replacement of the power source according toa prescribed power source replacement regime, the prescribed powersource replacement regime comprising the replacement of the power sourceon a prescribed repeated basis similar to administering a pill under aprescribed pill-based medication regime.

Another aspect of the invention provides systems and methods thatinclude a stimulation electrode assembly comprising an elongated leadsized and configured to be implanted within an adipose tissue region.The lead includes an electrically conductive portion to apply electricalstimulation to nerve or muscle in the adipose tissue region and at leastone expandable anchoring structure deployable from the lead to engageadipose tissue and resist dislodgment and/or migration of theelectrically conductive portion within the adipose tissue region.

Another aspect of the invention provides a functional kit for thestimulation electrode assembly, together with instructions forimplanting and operating the assembly in a targeted adipose tissueregion.

Other features and advantages of the inventions are set forth in thefollowing specification and attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plane view of an implant system for treating urinaryincontinence in humans.

FIG. 2 is a plane view of a system of surgical tools that can be use toimplant the system shown in FIG. 1.

FIG. 3 is a plane view of test screening system that can used when thesystem shown in FIG. 1 is implanted in a two stage surgical procedure.

FIG. 4 is a plane view of a clinical programmer that can be used inconjunction with the system shown in FIG. 1.

FIGS. 5A and 5B are anterior anatomic views of the system shown in FIG.1 after implantation in an adipose tissue region at or near the pubicsymphysis.

FIG. 6 is an anterior anatomic view of the pelvic girdle in a human.

FIG. 7 is a lateral section view of the pelvic girdle region shown inFIG. 6.

FIG. 8 is an inferior view of the pelvic girdle region shown in FIG. 6.

FIGS. 9 to 20 illustrate steps of implanting the system shown in FIG. 1in a single surgical procedure.

FIGS. 21 to 30 illustrate steps of implanting the system shown in FIG. 1in a two stage surgical procedure.

FIG. 31 is an anterior anatomic view of the system shown in FIG. 1 afterimplantation, showing the use of the clinical programmer shown in FIG. 4to program the system.

FIG. 32 is an anterior anatomic view of the system shown in FIG. 1 afterimplantation, showing the use of a controller to operate the system.

FIG. 33 is an anatomic section view of a region of adipose tissue.

FIGS. 34 and 35 are anatomic section views of the adipose tissue regionshown in FIG. 33 with a single lead and electrode associated with thesystem shown in FIG. 1, after having been implanted.

FIG. 36 is a side interior view of a representative embodiment of a leadof the type shown in FIGS. 34 and 35.

FIG. 37 is an end section view of the lead taken generally along line37-37 in FIG. 36.

FIG. 38A is an elevation view, in section, of a lead and electrode ofthe type shown in FIGS. 34 and 35 residing within an introducer sheathfor implantation in a targeted tissue region, the anchoring membersbeing shown retracted within the sheath.

FIG. 38B is an elevation view, in section, of a lead and electrode ofthe type shown in FIG. 39 after withdrawal of the introducer sheath 32,the anchoring members being shown extended for use.

FIG. 39 is an elevation view of an alternative representative embodimentof lead having anchoring members.

FIG. 40 is a plane view of a kit packaging the implant system shown inFIG. 1 for use.

FIG. 41 is a plane view of two kits that facilitate the implantation ofan implant system shown in FIG. 1 in a two stage surgical procedure.

FIG. 42 is an anterior anatomic view of an embodiment of an externalpulse generator coupled to a lead and electrode during the test stage ofa two step surgical procedure for implanting the system shown in FIG. 1.

The invention may be embodied in several forms without departing fromits spirit or essential characteristics. The scope of the invention isdefined in the appended claims, rather than in the specific descriptionpreceding them. All embodiments that fall within the meaning and rangeof equivalency of the claims are therefore intended to be embraced bythe claims.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The various aspects of the invention will be described in connectionwith the treatment of urinary incontinence by the bilateral stimulationof the left and/or right branches of the dorsal genital nerves using asingle lead implanted in adipose or other tissue in the region at ornear the pubic symphysis. That is because the features and advantages ofthe invention are well suited for this purpose. Still, it should beappreciated that the various aspects of the invention can be applied inother forms and in other locations in the body to achieve otherobjectives as well.

I. System Overview

A. The Implant System

FIG. 1 shows an implant system 10 for treating urinary incontinence inhumans.

The implant system 10 includes an implantable lead 12 having a proximaland a distal end. The proximal end carries a plug 22, which is desirablyof an industry-standard size, for coupling to an industry-sizedconnector 14 on a implantable pulse generator 18. The distal endincludes at least one electrically conductive surface, which will alsoin shorthand be called an electrode 16. The lead electrically connectsthe electrode 16 to the connector 14, and this to the implantable pulsegenerator 18 itself, while electrically insulating the wire from thebody tissue except at the electrode 16.

The lead 12 and electrode 16 are sized and configured to be implantedpercutaneously in tissue, and to be tolerated by an individual duringextended use without pain or discomfort. The comfort is both in terms ofthe individual's sensory perception of the electrical waveforms that theelectrode applies, as well as the individual's sensory perception of thephysical presence of the electrode and lead. In both categories, thelead 12 and electrode 16 are desirably “imperceptible.”

In particular, the lead 12 and electrode 16 are sized and configured toreside with stability in soft or adipose tissue 54 in the lower anteriorpelvic region of the body (see FIG. 5). It has been discovered that,when properly placed in this region, a single lead/electrode 16 isuniquely able to deliver electrical stimulation current simultaneouslyto both left and right branches of the dorsal genital nerves, presentnear the clitoris in a female and near the base of the penis of a male(see FIGS. 5A and 5B). Specific features of the lead 12 and electrode 16that make them well suited for this purpose, as well as other purposes,will be described in greater detail later.

The implant system 10 also includes an implantable pulse generator 18.The implantable pulse generator 18 includes a circuit that generateselectrical stimulation waveforms. An on-board battery provides thepower. The implantable pulse generator 18 also includes an on-board,programmable microprocessor, which carries embedded code. The codeexpresses pre-programmed rules or algorithms under which the desiredelectrical stimulation waveforms are generated by the circuit. The metalcase of the implantable pulse generator also serves as the returnelectrode for the stimulus current introduced by the lead/electrode whenoperated in a monopolar configuration.

The implantable pulse generator 18 is sized and configured to beimplanted subcutaneously in tissue, desirably in a subcutaneous pocketremote from the electrode 16 and using a minimally invasive surgicalprocedure. As shown in FIGS. 5A and 5B, the implantation site cancomprise a tissue region on the posterior hip. Alternatively, theimplantation site can comprise a more medial tissue region in the lowerabdomen. There, the implantable pulse generator 18 can reside forextended use without causing pain and/or discomfort and/or withouteffecting body image.

The implant system 10 includes an external patient controller 26 (seeFIG. 5A also). The controller 26 is sized and configured to be held bythe individual to transcutaneously activate and deactivate or modify theoutput of the implantable pulse generator. The controller 26 may, e.g.,be a simple magnet that, when placed near the site where the implantablepulse generator 18 is implanted (see FIG. 32), toggles a magnetic switchwithin the implantable pulse generator 18 between an on condition and anoff condition, or advances through a sequence of alternative stimulusmodes pre-programmed by the clinician into implantable pulse generator18. Alternatively, the controller 26 may comprise more sophisticatedcircuitry that would allow the individual to make these selectionsthrough an RF field (magnetic and/or electric) that passes through theskin and tissue within an arm's length distance from the implantablepulse generator.

According to its programmed rules, when switched on, the implantablepulse generator 18 generates prescribed stimulation waveforms throughthe lead 12 and to the electrode 16. These waveforms bilaterallystimulate the left and right branches of the dorsal genital nerves in amanner that achieves the desired physiologic response.

It has been discovered that bilateral stimulation of the dorsal genitalnerves achieved by placement of a single electrode 16 at a uniquelocation in the body (which will be described in greater detail later),achieves the desired physiologic result of consistently and effectivelyinhibiting unwanted bladder contractions. This makes possible thetreatment of UUI and/or mixed UUI and SUI or other urinary continencedysfunctions. Using the controller 26, the individual may turn on orturn off the continence control waveforms at will or adjust thestrength, depending, e.g., upon the time of day or fluid consumption.

B. Physician Surgical Tools

The implant system 10 shown in FIG. 1 makes desirable a system ofphysician surgical tools (shown in FIG. 2) to facilitate implantation ofthe implant system 10 in the intended way, desirably on an outpatientbasis.

The surgical tool system 28 shown in FIG. 2 includes a needle 30 (ortrocar) and a companion introducer sleeve 32. The sleeve 32 iselectrically insulated or insulated except at its tip. The needle 30 isalso electrically insulated, except at its tip.

The tool system 28 also includes an external pulse generator 34, whichoperates to generate stimulation wave pulses of the same type as theimplantable pulse generator 18. The external pulse generator 34 includesa connector cable 36 to couple the external pulse generator 34 to theneedle 30. A patch electrode 38 is also included, which is to be placedon the skin of the individual and coupled to the external pulsegenerator 34, to serve as a return path for the stimulation waveforms.In use (as will be described in greater detail later), and with theindividual subject to anesthesia, the needle 30 is placed tip-first intothe sleeve 32, and the sleeve 32 and needle 30 are advancedpercutaneously into the targeted tissue region in the lower abdomen. Theneedle 30 and return electrode 38 are coupled to the external pulsegenerator 34, to apply stimulation waveforms through the tip of theneedle concurrent with positioning of the needle 30.

By monitoring anal pressure and/or contractions, patient-reportedsensations, and/or bladder contractions in concert with applyingstimulation waveforms through the tip of the needle 30—e.g., usingstandard clinical urodynamic monitoring instruments—the physician canprobe the tissue region, penetrating and withdrawing the needle 30 asnecessary in a minimally invasive way, until a subcutaneous locationwhere optimal intended stimulation results are realized.

Once this location is found, the needle 30 can be withdrawn from thesleeve 32, followed by insertion of the lead 12, electrode-first,through the sleeve 32 into the location. Then the sleeve 32 is withdrawnwhich fixes the location of the electrode 16, as will be described ingreater detail later. Desirably, the external pulse generator 34 iscoupled to the lead 12 through the cable 36 to confirm that theelectrode 16 resides in the desired location before tunneling the lead.

The tool system 28 also includes a tunneling tool 40. In use (as willalso be described later), and with an individual still possibly subjectto only local anesthesia, the tunneling tool 40 is manipulated by thephysician to route the lead 12 subcutaneously to the pocket site wherethe implantable pulse generator 18 is to be implanted. The lead 12 iscoupled to the implantable pulse generator 18. The lead 12 andimplantable pulse generator 18 are placed into the subcutaneous pocket,which is sutured closed.

Using the surgical tool system 28, the implant system 10 can beimplanted in the manner shown in FIGS. 5A and 5B.

C. Test Screening Tools

In the above description, the surgical tool system 28 is used to implantthe implant system 10 in a single surgical procedure. Alternatively, anddesirably, a two-stage surgical procedure can be used.

The first stage comprises a screening phase that performs teststimulation using a temporary external pulse generator to evaluate if anindividual is a suitable candidate for extended placement of theimplantable pulse generator. The first stage can be conducted, e.g.,during a nominal two week period. If the patient is a suitablecandidate, the second stage can be scheduled, which is the implantationof the implantable pulse generator 18 itself, as described above.

A test screening system 42 (shown in FIG. 3) can be provided tofacilitate the two stage procedure. The test screening system 42includes the lead 12 and electrode 16, which are the same as thoseincluded with the implant system 10 shown in FIG. 1. The test screeningsystem 42 also includes a percutaneous extension cable 44, which issized and configured to be tunneled subcutaneously from the pocket siteto a remote site (e.g. 5-10 cm medially) where it exits the skin. Thepercutaneous extension cable has a proximal and distal end. The proximalend carries a receptacle 46 for connection to the industry-standard sizeplug on the end of the lead 12. The distal end of the percutaneousextension cable 44 carries a plug 48 that couples to an external testcable 88, which itself is coupled to an external pulse generator 34,which the test screening system 42 further includes.

The external pulse generator 34 can also be of the same type previouslydescribed in connection with the surgical tool system 28. In thisarrangement, the patch return electrode 38 is included, or is otherwiseavailable, to be coupled to the external pulse generator 34. Analternative form of an external pulse generator 34, usable with the testscreening system 42, will be described later.

The test screening system 42 also includes the external test cable 88.One end of the external test cable 88 carries a plug 90 to connect tothe external pulse generator 34. The other end of the external testcable 88 includes a connector to receive the plug 48 of the percutaneousextension cable 44. This end of the external test cable 88 can also besized and configured to connect directly to the surface patch electrode38.

In use (as will be described in greater detail later), the physicianmakes use of the needle 30 and sleeve 32 of a surgical tool system 28 toimplant the electrode 16 and lead 12 in the desired location, in themanner previously described. These components of a surgical tool system28 can be provided with the test screening system 42. The percutaneousextension cable 44 is coupled to the lead 12. Using the tunneling tool40 of a surgical tool system 28, the physician subcutaneously tunnelsthe percutaneous extension cable 44 to a suitable exit site, which isdesirably remote from the site where the pocket for the implanted pulsegenerator is to be created in the second phase. Further details of thiswill be described in greater detail later. A short length of thepercutaneous extension cable 44 that carries the plug 48 extends outsidethe exit site, for coupling the electrode 16 to the external pulsegenerator 34 via the test cable 88. The return patch electrode 38 isalso coupled to the external pulse generator 34.

The individual patient wears the external pulse generator 34 and returnpatch electrode 38 for the prescribed test period. The external pulsegenerator 34 supplies the prescribed stimulation regime. If animprovement in urinary continence is achieved, the second phase iswarranted. In the second phase, the percutaneous extension cable 44 isremoved and discarded, and the implantable pulse generator is connectedto the lead 12 and installed in a pocket remote from the electrode 16 inthe manner previously described.

D. Clinician Tools

A clinical tool system 50 is desirably provided to condition theimplantable pulse generator 18 to perform in the intended manner.

In the embodiment shown in FIG. 4, the clinical tool system 50 includesa clinical programmer 52 and perhaps a separate wand connected to theprogrammer by a cable. The clinical programmer 52 can be placed intotranscutaneous communication with an implantable pulse generator 18,e.g., through a radio-frequency magnetic and/or electric field (see FIG.31), or using a wand. The clinical programmer 52 may incorporate acustom program operating on a handheld computer or other personaldigital appliance (PDA). Should a personal digital appliance be usedwith a custom program, then the circuitry necessary to generate anddetect the RF fields used to communicate with the implantable pulsegenerator would be located in the wand. The clinical programmer 52 orPDA includes an on-board microprocessor powered by a rechargeable,on-board battery (not shown). The microprocessor carries embedded codewhich may include pre-programmed rules or algorithms that allow aclinician to remotely download program stimulus parameters and stimulussequences parameters into the implantable pulse generator. Themicroprocessor of the clinical programmer 52 is also desirably able tointerrogate the implantable pulse generator and upload operational datafrom the implantable pulse generator.

II. Implanting the Implant System

A. The Anatomic Landmarks

As already described, certain components of the implant system 10 aresized and configured to be implanted in adipose tissue in a particularlocation in an individual's lower abdomen, where it has been discoveredthat effective bilateral stimulation of both the left and right branchesof the dorsal genital nerves can be achieved with a single electrode.The main anatomic landmark guiding the unique placement of thesecomponents is the pubic symphysis.

As FIG. 6 shows, the hip bones are two large, irregularly shaped bones,each of which develops from the fusion of three bones, the ilium,ischium, and pubis. The ilium is the superior, fan-shaped part of thehip bone. The ala of the ilium represents the spread of the fan. Theiliac crest represents the rim of the fan. It has a curve that followsthe contour of the ala between the anterior and posterior superior iliacspines.

As FIGS. 6 and 7 show, the sacrum is formed by the fusion of fiveoriginally separate sacral vertebrae. The hip bones are joined at thepubic symphysis anteriorly and to the sacrum posteriorly to form thepelvic girdle (see FIG. 6). The pelvic girdle is attached to the lowerlimbs. Located within the pelvic girdle are the abdominal viscera (e.g.,the ileum and sigmoid colon) and the pelvic viscera (e.g., the urinarybladder and female reproductive organs such as the uterus and ovaries).

Within this bony frame (see FIGS. 6 and 7), the pudendal nerve isderived at the sacral plexus from the anterior divisions of the ventralrami of S2 through S4. The pudendal nerve extends bilaterally, inseparate branches on left and right sides of the pelvic girdle. Eachbranch accompanies the interior pudendal artery and leaves the pelvisthrough the left and right greater sciatic foramens between thepiriformis and coccygeus muscles. The branches hook around the ischialspine and sacrospinous ligament and enter the skin and muscles of theperineum through the left and right lesser sciatic foramen.

As shown in FIG. 8, the bilateral left and right braches extendanteriorly through the perineum, each ending as the dorsal genital nerveof the penis or clitoris. The genital nerves are the chief sensory nerveof the external genitalia. The Figures are largely based upon theanatomy of a female, but the parts of the male perineum are homologuesof the female.

As FIG. 8 shows, in the male and female, adipose tissue 54 overlays thepubic symphysis. The bilateral branches of the genital nerves innervatethis tissue region. In the female, this tissue region is known as themons pubis. In the male, the penis and scrotum extend from this region.Further discussion regarding the fixation of the lead 12 and electrode16 in adipose tissue 54 will be described later.

B. Implantation Methodology

Representative surgical techniques will now be described to place anelectrode 16 and lead 12 in a desired location in adipose tissue 54 ator near the pubic symphysis. It is this desired placement that makespossible the bilateral stimulation of both left and right branches ofthe dorsal genital nerves with a single lead 12 to provide continence.

Before implantation, it is recommended that an oral broad spectrumantibiotic is given and continued for 5 days. The lower abdomen from thepubic symphysis to umbilicus and from the anterior iliac spinesbilaterally are prepped with Betadine (or Hibiclens Solutions for casesof Betadine allergy).

As before generally described, implantation of the implant system 10shown in FIG. 1 can entail a single surgical procedure or a two-stepsurgical procedure. Each will now be described.

1. Single Surgical Procedure

FIGS. 9 to 20 illustrate steps of implanting an implant system 10 in asingle surgical procedure.

Locating the Lead/Electrode

The site for the needle puncture 60 is located midline or near-midline,near the inferior border of the pubic symphysis aiming toward theclitoris (or the base of the penis in males). Local anesthesia—e.g., 1%Lidocaine (2-5 ccs) or equivalent—is injected prior to making theanticipated needle 30 puncture site.

Once local anesthesia is established, as shown in FIG. 9, the needle 30and sleeve 32 are advanced percutaneously into the anesthetized site 60to a depth necessary to reach the target site between the pubicsymphysis and the clitoris. As FIG. 10 shows, the needle 30 is coupledto the external pulse generator 34 (via the cable 36), to applystimulation waveforms through the needle tip concurrent with positioningof the needle 30. A patch electrode 38 placed on the skin of theindividual is also coupled to the external pulse generator 34 to serveas a return path for the stimulation waveforms.

The physician monitors anal pressure, and/or anal sphinctercontractions, patient-reported sensations, and/or bladder contractionsin concert with applying stimulation waveforms through the needle tip,penetrating and withdrawing the needle 30 as necessary in a minimallyinvasive way, until a subcutaneous location where bilateral stimulationof both left and right branches of the genital nerves results.

As FIG. 11 shows, once this location is found, the external pulsegenerator 34 is disconnected and the needle 30 is withdrawn from thesleeve 32. As FIG. 12 shows, the lead 12, electrode-first, is passedthrough the sleeve 32 into the location. As FIG. 13 shows, theintroducing sleeve 32 is withdrawn, which fixes the location of theelectrode 16. Desirably, the external pulse generator 34 is againcoupled to the lead 12 via the cable 36 (see FIG. 14) to applystimulation pulses through the electrode 16, to confirm that theelectrode 16 resides in the location previously found. This aspect ofthe deployment of the electrode 16 will be described in greater detaillater.

Forming the Implantable Pulse Generator Pocket

The incision site for forming the subcutaneous pocket 56 for theimplantable pulse generator comprises a lateral 2 cm incision 98 (seeFIG. 15), which, in FIG. 15, is located two finger-breaths medial to theanterior iliac spine and made in the direction of the dermatomal skinline. Local anesthesia—e.g., 1% Lidocaine (2-5 ccs) or equivalent—isinjected before making the incision in this site.

Once local anesthesia is established, the incision for the pocket 56 ismade using a skin knife. The incision is made large enough to accept theindex or dissecting finger of the implant physician. As FIG. 15 shows, asubcutaneous pocket 56 is made to accept the implantable pulse generator18 using blunt dissection techniques of the subcutaneous tissues. Theaxis of the pocket 56 follows the direction of the dermatomal skin lineand the entrance site of the lead 12/electrode 16.

Tunneling the Lead

Having developed the subcutaneous pocket 56 for the implantable pulsegenerator 18, a subcutaneous tunnel is formed for connecting theelectrode 16 to the implantable pulse generator 18. First (as FIG. 15shows), the size of the needle puncture site 60 is increased using askin knife. Next, the tunneling tool 40 (shown in FIG. 2) is passedthrough the pocket incision site 98 (see FIG. 16) toward and through theneedle puncture site 60. The tunneling tool 40 desirably includes aremovable blunt tip 62 (see FIG. 2) that is present during tunneling,but that is removed once passage through the distant incision site 60occurs. With the blunt tip 62 removed, the lead 12 can be passed throughthe open lumen of the tunneling tool 40 to the pocket incision site 98,as FIG. 17 shows. Withdrawal of the tunneling tool 40 delivers the plug22 of the lead 12 through the pocket incision 98 into the proceduralfield.

It should be appreciated that, in an alternative technique, a tunnelingtool 40 comprising a stylet and sheath can be placed at the site of theneedle puncture site and advanced toward the pocket incision. Removal ofthe stylet allows the physician to pass the lead 12 through the sheathto the pocket incision site, followed by removal of the sheath.

Connecting the Lead to the Implantable Pulse Generator

Once the lead 12 has been tunneled to the pocket incision site (see FIG.18), the plug 22 can be connected to the implantable pulse generator 18.

Implanting the Implantable Pulse Generator

Once the lead 12 has been connected to the implantable pulse generator18, the lead 12 and v implantable pulse generator can be placed into thepocket 56 (as FIG. 19 shows). The implantable pulse generator 18 islocated approximately 1 cm from the surface of the skin; and the cableis oriented with an open loop of cable to allow for motion of theabdominal contents without transmitting forces along the cable and lead.

Both wound sites are irrigated with irrigation solutions (½ strengthbetadine or Hibiclens solution or equivalent). The skin sites are closedusing Derma-bond glue or stitches of 4-0 vicryl, as FIG. 20 shows.Dressing is desirably applied for about twenty-four hours. The incisionsare desirably kept dry for forty-eight hours.

2. Two Stage Surgical Procedure

FIGS. 21 to 30 illustrate steps of implanting an implant system 10 in atwo stage surgical procedure. As before described, the first stageinstalls the electrode 16 and lead 12 in the manner described above, andconnects the lead 12 to a temporary external pulse generator 34. If theuse of the external pulse generator 34 achieves the desired results, animplantable pulse generator is implanted in the second stage in themanner described above.

a. The First Stage

Tunneling the Lead and Percutaneous Extension Cable for Connection to anExternal Pulse Generator

The same preoperative antibiotics and skin prep as previously describedare performed. Under anesthesia, the electrode 16/lead 12 are locatedand tunneled to the site that will later (in stage 2) hold theimplantable pulse generator. In the first stage (see FIG. 21), the lead12 is connected to the percutaneous extension cable 44, which has beenearlier described and is shown in FIG. 3.

After placement of the electrode 16/lead 12 and the connection of thepercutaneous extension cable 44, as FIG. 22 shows, under anesthesia, afirst incision 64 is formed at the intended site of the pocket 56 forthe implantable pulse generator 18. As before described, this site 64 isgenerally located two finger-breaths medial to the anterior iliac spineand made in the direction of the dermatomal skin line. The size of theneedle puncture site 60 is also increased using a skin knife, inpreparation for tunneling.

As FIG. 23 shows, a tunneling tool 40 (shown in FIG. 2) is passedthrough the first incision 64 toward and through the needle puncturesite 60 (or vice versa), as previously described. The blunt tip 62 ofthe tunneling tool 40 is removed, and the percutaneous extension cable44 and connected lead 12 are passed through the open lumen of thetunneling tool 40 to the first incision site 64. Withdrawal of thetunneling tool 40 delivers the plug 48 of the percutaneous extensioncable 44 through the first incision 64 into the procedural field.

As FIG. 25 shows, a second incision site 66 is made across the pelvisaway from the first incision site 64. The percutaneous extension cable44 will be eventually routed to the second incision site 66. In thisway, should infection occur in the region where the percutaneousextension cable 44 extends from the skin, the infection occurs away fromthe region where the pocket 56 for the implantable pulse generator 18 isto be formed (i.e., at the first incision site 64). The first incisionsite 64 is thereby shielded from channel infection during the firststage, in anticipation forming a sterile pocket 56 for the implantablegenerator in the second stage.

More particularly, the tunneling tool 40 is advanced from the secondincision site 66 subcutaneously toward and through the first incisionsite 64 (or vice versa). As FIG. 26 shows, the blunt tip 62 of thetunneling tool 40 is removed, and the percutaneous extension cable 44 ispassed through the open lumen of the tunneling tool 40 to the secondincision site. Withdrawal of the tunneling tool 40 (see FIG. 27)delivers the plug 48 of the percutaneous extension cable 44 through thesecond incision 66 into the procedural field. A short length of thepercutaneous cable 44 is then secured externally to the skin withsterile tape 100. At this point the plug 48 at the end of thepercutaneous extension cable 44 is available for connection to theexternal test cable 88 (as FIG. 28 shows). The remainder of thepercutaneous cable 44 is located under the skin and is free of exposureto outside contamination. The sterile tape 100 covering the exit siteand the re-growth of tissue maintains this sterile barrier.

All wound sites are irrigated with irrigation solutions and closed usingDerma-bond glue or stitches of 4-0 vicryl, as FIG. 28 shows.

An external pulse generator 34 of the type previously described iscoupled to the exposed plug 48 of the percutaneous extension cablethrough an external test cable 88, as FIG. 28 shows. The patch electrode38 is placed on the skin and likewise coupled to the external pulsegenerator 34. The individual wears the external pulse generator 34(e.g., in a belt holster or taped to the skin) and return patchelectrode 38 (on the skin) for the prescribed test period. The externalpulse generator 34 supplies the prescribed stimulation regime. If animprovement in urinary continence is achieved during the test phase, thesecond phase of the surgical procedure is scheduled to proceed.

Instead of using an external pulse generator 34 as shown in FIG. 28, aneuromuscular stimulation device 68 can be used of the type described incopending U.S. patent application Ser. No. 10/777,771, filed Feb. 12,2004 and entitled “Portable Percutaneous Assemblies, Systems, andMethods for Providing Highly Selective Functional or TherapeuticNeurostimulation,” which is incorporated herein by reference. As shownin FIG. 42, the device 68 comprises a skin-worn patch or carrier, whichcan be carried, e.g., by use of a pressure-sensitive adhesive, withoutdiscomfort and without affecting body image on the torso of anindividual near the second incision. The carrier carries an on-boardelectronics pod, which generates the desired electrical currentpatterns. The pod houses microprocessor-based, programmable circuitrythat generates stimulus currents, time or sequence stimulation pulses,and logs and monitors usage. The electronics pod also includes anelectrode connection region, to physically and electrically couple thelead 12 to the circuitry of the electronics pod. The carrier alsoincludes a power input bay, to receive a small, lightweight, primarycell battery, which can be released and replaced as prescribed. Thebattery provides power to the electronics pod.

It is contemplated that, in a typical regime during stage one, theindividual will be instructed to regularly remove and discard thebattery (e.g., about once a day or once a week), replacing it with afresh battery. This arrangement simplifies meeting the power demands ofthe electronics pod. The use of the neuromuscular stimulation deviceparallels a normal, accustomed medication regime, with the battery beingreplaced at a prescribed frequency similar to an individualadministering a medication regime in pill form.

b. The Second Stage

Removing the Percutaneous Extension Cable

The same preoperative antibiotics and skin prep as previously describedare performed. In the second stage, the external pulse generator 34,return electrode 38, and external test cable 88 are disconnected fromthe percutaneous extension cable 44. As shown in FIG. 29, under localanesthesia, the first and second incisions 64 and 66 are reopened. Theconnection between the percutaneous extension cable 44 and lead 12 isdisconnected. The percutaneous extension cable 44 is removed through thesecond incision 66 and discarded, as FIG. 29 shows.

Forming the Implantable Pulse Generator Pocket

Following removal of the percutaneous extension cable 44, the firstincision 64 is enlarged to form a subcutaneous pocket 56 to accept theimplantable pulse generator 18 using blunt dissection techniques of thesubcutaneous tissues, as previously described (see FIG. 30). Theconnector 14 of the lead 12 is extracted through the pocket 56 into theprocedural field.

Connecting the Lead to the Implantable Pulse Generator

With the pocket 56 formed (see FIG. 18), and the lead 12 delivered intothe procedural field, the lead can now be connected to the implantablepulse generator 18.

Implanting the Implantable Pulse Generator

Once the lead 12 has been connected to the implantable pulse generator18, the lead 12 and implantable pulse generator can be placed into thepocket 56 (as FIG. 19 shows). The implantable pulse generator is locatedapproximately 1 cm from the surface of the skin; and the cable isoriented with an open loop of cable to allow for motion of the abdominalcontents without transmitting forces along the cable and lead.

The wound sites (first and second incisions) are irrigated withirrigation solutions (½ strength betadine or Hibiclens solution). Theskin sites are closed using Derma-bond glue or stitches of 4-0 vicryl,as FIG. 20 shows. Dressing is desirably applied for about twenty-fourhours. The incisions are desirably kept dry for forty-eight hours.

III. Features of the Lead and Electrode

A. Implantation in Adipose Tissue

Neurostimulation leads and electrodes that may be well suited forimplantation in muscle tissue are not well not suited for implantationin soft adipose tissue 54 in the targeted location at or near the pubicsymphysis. This is because adipose tissue 54 is unlike muscle tissue,and also because the vascularization and innervation of tissue at ornear the pubic symphysis is unlike tissue in a muscle mass. Musculartissue is formed by tough bundles of fibers with intermediate areolartissue. The fibers consist of a contractile substance enclosed in atubular sheath. The fibers lend bulk, density, and strength to muscletissue that are not found in soft adipose tissue 54. Muscles are alsonot innervated with sensory nerves or highly vascularized with bloodvessels to the extent found in the pubic region of the body.

Adipose tissue 54 (see FIG. 33) consists of small vesicles, calledfat-cells, lodged in the meshes of highly vascularized areolar tissuecontaining minute veins, minute arteries, and capillary blood vessels.The fat-cells vary in size, but are about the average diameter of 1/500of an inch. They are formed of an exceedingly delicate protoplasmicmembrane, filled with fatty matter, which is liquid during life andturns solid after death. They are round or spherical where they have notbeen subject to pressure; otherwise they assume a more or less angularoutline. The fat-cells are contained in clusters in the areolae of fineconnective tissue, and are held together mainly by a network ofcapillary blood vessels, which are distributed to them.

The lead 12 and electrode 16 are sized and configured to be insertedinto and to rest in soft adipose tissue 54 (see FIG. 34) in the lowerabdomen without causing pain or discomfort or impact body image.Desirably, the lead 12 and electrode 16 can be inserted using a small(e.g., smaller than 16 gauge) introducer with minimal tissue trauma. Thelead 12 and electrode 16 are formed from a biocompatible andelectrochemically suitable material and possess no sharp features thatcan irritate tissue during extended use. Furthermore, the lead 12 andelectrode 16 possess mechanical characteristics including mechanicalcompliance (flexibility) along their axis (axially), as well asperpendicular to their axis (radially), and unable to transmit torque,to flexibly respond to dynamic stretching, bending, and crushing forcesthat can be encountered within soft, mobile adipose tissue 54 in thisbody region without damage or breakage, and to accommodate relativemovement of the implantable pulse generator coupled to the lead 12without imposing force or torque to the electrode 16 which tends todislodge the electrode.

Furthermore, the lead 12 and electrode 16 desirably include an anchoringmeans 70 for providing retention strength to resist migration within orextrusion from soft, mobile adipose tissue 54 in this body region inresponse to force conditions normally encountered during periods ofextended use. In addition, the anchoring means 70 is desirably sized andconfigured to permit the electrode 16 position to be adjusted easilyduring insertion, allowing placement at the optimal location wherebilateral stimulation of the left and right branches of the genitalnerves occurs. The anchoring means 70 functions to hold the electrode atthe implanted location despite the motion of the tissue and small forcestransmitted by the lead due to relative motion of the connectedimplantable pulse generator due to changes in body posture or externalforces applied to the abdomen. However, the anchoring means 70 shouldallow reliable release of the electrode 16 at higher force levels, topermit withdrawal of the implanted electrode 16 by purposeful pulling onthe lead 12 at such higher force levels, without breaking or leavingfragments, should removal of the implanted electrode 16 be desired.

B. The Lead

FIGS. 36 and 37 show a representative embodiment of a lead 12 andelectrode 16 that provide the foregoing features. The lead 12 comprisesa molded or extruded component 72, which encapsulates a coiled strandedwire element 74. The wire element may be bifilar, as shown in FIG. 36.The molded or extruded lead 12 can have an outside diameter as small asabout 1 mm. The lead 12 may be approximately 10 cm to 30 cm in length.

The coil's pitch can be constant or, as FIG. 36 shows, the coil's pitchcan alternate from high to low spacing to allow for flexibility in bothcompression and tension. The tight pitch will allow for movement intension, while the open pitch will allow for movement in compression.

C. The Electrode

The electrode 16 or electrically conductive surface can be formed fromPtIr (or, alternatively, 316L stainless steel) and possess a conductivesurface of approximately 10 mm²-20 mm². This surface area providescurrent densities up to 2 mA/mm² with per pulse charge densities lessthan 0.5 μC/mm².

FIG. 35 shows a monopolar electrode configuration. In use, the casing ofthe implantable pulse generator 18 serves as a return electrode. In themonopolar electrode arrangement, the single electrode 16 is provided atthe distal-most end.

Alternatively, one or more additional conductive surfaces can beprovided, spaced proximally from the tip electrode 16, to provide abipolar electrode configuration.

D. The Anchoring Means

In the illustrated embodiment (see FIG. 38B), the anchoring means 70takes the form of an array of flexible tines 76 or filaments proximal tothe distal-most electrode 16. The tines 76 are desirably presentrelatively large, planar surfaces, and are placed in multiple rowsaxially along the lead 12. The tines 76 are normally biased toward aradially outward condition into tissue. In this condition, the largesurface area and orientation of the tines 76 allow the lead 12 to resistdislodgement or migration of the electrode 16 out of the correctlocation in the surrounding tissue. In the illustrated embodiment, thetines 76 are biased toward a proximal-pointing orientation, to betterresist proximal migration of the electrode 16 with lead tension. Thetines 76 are desirably made from a polymer material, e.g., highdurometer silicone, polyurethane, or polypropylene, bonded to or moldedwith the lead 12.

The tines 76 can be deflected toward a distal direction in response toexerting a pulling force on the lead 12 at a threshold axial forcelevel, which is greater than expected day-to-day axial forces. The tines76 are sized and configured to yield during proximal passage throughtissue in result to such forces, causing minimal tissue trauma, andwithout breaking or leaving fragments, despite the possible presence ofsome degree of tissue in-growth. This feature permits the withdrawal ofthe implanted electrode 16, if desired, by purposeful pulling on thelead 12 at the higher axial force level.

Desirably, the anchoring means 70 is prevented from fully engaging bodytissue until after the electrode 16 has been deployed. The electrode 16is not deployed until after it has been correctly located during theimplantation (installation) process.

More particularly, as before described, the lead 12 and electrode 16 areintended to be percutaneously introduced through a sleeve 32 shown inFIG. 2 (this is also shown in FIG. 12). As shown in FIG. 38A, the tines76 assume a collapsed condition against the lead 12 body when within thesleeve 32. In this condition, the tines 76 are shielded from contactwith tissue. Once the location is found, the sleeve 32 can be withdrawn,holding the lead 12 and electrode 16 stationary (see FIG. 38B. Free ofthe sleeve 32, the tines 76 spring open to assume their radiallydeployed condition in tissue, fixing the electrode 16 in the desiredlocation.

The position of the electrode 16 relative to the anchoring means 70, andthe use of the sleeve 32, allows for both advancement and retraction ofthe electrode delivery sleeve during implantation while simultaneouslydelivering test stimulation. The sleeve 32 can be drawn back relative tothe lead 12 to deploy the electrode 16 anchoring means 70, but only whenthe physician determines that the desired electrode location has beenreached. The withdrawal of the sleeve 32 from the lead 12 causes theanchoring means 70 to deploy without changing the position of electrode16 in the desired location (or allowing only a small and predictable,set motion of the electrode). Once the sleeve 32 is removed, theflexible, silicone-coated or polyurethane-coat lead 12 and electrode 16are left implanted in the tissue.

As shown in FIG. 39, the anchoring means 70 can include an open-formconical structure 100 proximal to the distal-most electrode 16, alone orin combination with one or more arrays of flexible tines 76 spaced moreproximally away from the electrode. In the illustrated embodiment, thestructure 100 comprises an array of circumferentially spaced-apart tines102 joined by cross members 104, thereby forming a conically shapedbasket structure that increases in diameter (i.e., by tapering radiallyoutward) with distance from the electrode 12. The tines 102 and crossmembers 104 are desirably made from flexible or resilient wire orpolymer material, so that the structure 100 can be collapsed backagainst the lead 12 into a low profile for introduction through thesleeve 32. Withdrawal of the sleeve 32 frees the structure 100 toresiliently spring into the open-form conical shape shown in FIG. 39.The structure 100 provides localized stabilization for the more distalregions of the lead 12, including the electrode 16, which is additive tothe stabilization provided to the more proximal regions of the lead 12by the more proximally spaced tines 76. Together, the structure 100 andthe tines 76 provide complementary (“belt-and-suspenders”) resistanceagainst migration of the lead 12 and electrode 16 within mobile adiposetissue 54 in response to forces that tend to flex or twist the moredistal regions of the lead 12 relative to more proximal regions of thelead 12.

IV. Kits

As FIGS. 40 and 41 show, the various tools and devices as just describedcan be consolidated for use in functional kits 78, 80, and 82. The kits78, 80, and 82 can take various forms. In the illustrated embodiment,each kit 78, 80, and 82 comprises a sterile, wrapped assembly. Each kit78, 80, and 82 includes an interior tray 84 made, e.g., from die cutcardboard, plastic sheet, or thermo-formed plastic material, which holdthe contents. Each kit 78, 80, and 82 also preferably includesdirections 86 for using the contents of the kit to carry out a desiredprocedure.

The directions 86 can, of course vary. The directions 86 shall bephysically present in the kits, but can also be supplied separately. Thedirections 86 can be embodied in separate instruction manuals, or invideo or audio tapes, CD's, and DVD's. The instructions 86 for use canalso be available through an internet web page.

The arrangement and contents of the kits 78, 80, and 82 can vary. Forexample, in FIG. 40, a representative kit 78 is shown for carrying out asingle stage implant procedure as previously described. The kit 78includes the implant system 10 comprising the implantable lead 12 andelectrode 16, an implantable pulse generator 18, and an externalcontroller 26. The kit 78 also includes the surgical tool system 28comprising the needle 30, sleeve 32, and tunneling tool 40. An externalpulse generator 34 can also be provided, but this device will typicallybe available in the surgical suite. The instructions 86 for use in thekit 78 direct use of these instruments to implant the lead 12 andelectrode 16, form the subcutaneous pocket, tunnel the lead 12, andimplant the implantable pulse generator 18 in the subcutaneous pocket inthe manner previously described and as shown in FIGS. 9 to 20. Theinstructions 86 for use can also direct use of the external controller26 to operate the implantable pulse generator 18, as well as use of aclinician programmer 52 to program the implantable pulse generator 18.

As another example, in FIG. 41, two representative kits 80 and 82 areshown that, together, allow the physician to carry out a two stagesurgical procedure. The first kit 80 includes the test screening system42 comprising the implantable lead 12 and electrode 16, the percutaneousextension cable 44, and an external pulse generator 34 and patchelectrode 38 for use on a temporary basis during the screening phase.The kit 80 also includes the surgical tools system comprising the needle30, sleeve 32, and tunneling tool 40. The instructions 86 for use directuse of these instruments to install the lead 12 and electrode 16, tunnelthe lead 12 and percutaneous cable 44, and connect the temporaryexternal pulse generator 34 during a first surgical stage for patientscreening purposes, in the manner previously described and as shown inFIGS. 21 to 27. The instructions 86 for use can also direct use of theexternal pulse generator 34.

The second kit 82 contains the instruments to carry out the second stageof the procedure. The second kit 82 includes an implantable pulsegenerator 18, an external controller 26, and a tunneling tool 40. Theinstructions 86 for use direct use of these components to remove thepercutaneous cable 44 and couple the lead 12 to the implantable pulsegenerator 18, and implant the implantable pulse generator 18 in asubcutaneous pocket in the manner previously described and as shown inFIGS. 28 to 30 and 18 to 20. The instructions 86 for use can also directuse of the external controller 26 to operate the implantable pulsegenerator, as well as use of a clinician programmer to program theimplantable pulse generator.

Various features of the invention are set forth in the following claims.

1. A stimulation electrode assembly comprising: an elongated lead sizedand configured to be implanted in adipose tissue at or near a pubicsymphysis, the lead including at least one electrode to apply electricalstimulation to a nerve in the adipose tissue, the nerve affectingurinary function, and at least one expandable anchoring structuredeployable from the lead to engage the adipose tissue and resistdislodgment and/or migration of the lead and electrode within theadipose tissue, the expandable anchoring structure sized and configuredto form an open structure that enlarges in diameter from distal toproximal to resist proximal passage of the lead and electrode throughthe adipose tissue.
 2. An assembly according to claim 1 wherein thenerve comprises a left and/or right branch of the dorsal genital nerve.3. An assembly according to claim 1 wherein the expandable anchoringstructure is deployable between a collapsed condition along the lead andan expanded condition extending outward of the lead.
 4. An assemblyaccording to claim 3 wherein the expandable anchoring structure, when inthe expanded condition, assumes an open, proximal-pointing configurationthat resists proximal passage of the lead through adipose tissue inresponse to a pulling force that is less than or equal to a thresholdaxial force level.
 5. An assembly according to claim 4 wherein the open,proximal-pointing configuration yields to permit proximal passage of thelead through adipose tissue in response to a pulling force that isgreater than the threshold axial force level.
 6. An assembly accordingto claim 3 further including a sleeve having an interior bore sized andconfigured to create percutaneous access to the adipose tissue, theinterior bore retaining the expandable anchoring structure in thecollapsed condition to accommodate passage of the lead through the boreinto the adipose tissue.
 7. An assembly according to claim 3 wherein theexpandable anchoring structure is normally biased toward the expandedcondition.
 8. An assembly according to claim 7 further including asleeve having an interior bore sized and configured to createpercutaneous access to the adipose tissue, the interior bore retainingthe expandable anchoring structure in the collapsed condition toaccommodate passage of the lead through the bore into the adiposetissue, and wherein, upon passage into the adipose tissue region, theexpandable anchoring structure returns toward the normally biasedexpanded condition.
 9. An assembly according to claim 1 wherein theexpandable anchoring structure comprises an array of circumferentiallyspaced-apart, radiating filaments.
 10. An assembly according to claim 1comprising at least two expandable anchoring structures.
 11. An assemblyaccording to claim 1 wherein the lead includes a distal section, andwherein the electrically conductive portion is at or near the distalsection, and wherein the expandable anchoring structure is proximal tothe electrically conductive portion.
 12. An assembly according to claim1 wherein the expandable anchoring structure comprises a polymermaterial.
 13. A system to affect urinary function, the systemcomprising: a stimulation electrode assembly, the assembly comprising anelongated lead, the lead including an electrically conductive portionand at least one expandable anchoring structure deployable from thelead, the electrically conductive portion and the at least oneexpandable anchoring structure sized and configured to be implanted inan adipose tissue region at or near a pubic symphysis innervated by anerve affecting urinary function, the electrically conductive portionsized and configured to apply electrical stimulation to the nerve in theadipose tissue region affecting urinary function, the expandableanchoring structure sized and configured to engage the adipose tissueand resist dislodgment and/or migration of the electrically conductiveportion within the adipose tissue region, and an implantable pulsegenerator sized and configured to be implanted in subcutaneous tissue inan anterior pelvic region remote from the at least one electricallyconductive portion, and to convey electrical stimulation waveforms tothe stimulation electrode assembly to affect urinary function.
 14. Asystem according to claim 13 wherein the adipose tissue region isinnervated by a left and/or right branch of the dorsal genital nerve.15. A kit comprising: a stimulation electrode assembly comprising anelongated lead sized and configured to be implanted in an adipose tissueregion at or near a pubic symphysis, the lead including at least oneelectrode to apply electrical stimulation to a nerve in the adiposetissue region, the nerve affecting urinary function, and at least oneexpandable anchoring structure deployable from the lead to engage theadipose tissue and resist dislodgment and/or migration of the lead andelectrode within the adipose tissue region, the expandable anchoringstructure sized and configured to form an open structure that enlargesin diameter from distal to proximal to resist proximal passage of thelead and electrode through the adipose tissue region, and instructionsfor implanting the electrode and expandable anchoring structure in theadipose tissue region at or near the pubic symphysis, and deploying theexpandable anchoring structure in the adipose tissue region to resistdislodgment and/or migration of the lead and electrode within theadipose tissue.
 16. A kit according to claim 15 further including apulse generator to convey electrical stimulation waveforms to thestimulation electrode, and instructions for coupling the stimulationelectrode assembly to the pulse generator, and operating the pulsegenerator to convey electrical stimulation waveforms to the stimulationelectrode assembly to achieve stimulation of the nerve affecting urinaryfunction.
 17. A kit according to claim 16 wherein the instructionsinclude implanting the pulse generator in subcutaneous tissue in ananterior pelvic region remote from the at least one electrode.
 18. Amethod of stimulating a nerve to affect urinary function, the methodcomprising, providing a stimulation electrode assembly, the assemblycomprising an elongated lead sized and configured to be implanted inadipose tissue at or near a pubic symphysis, the lead including at leastone electrode to apply electrical stimulation to a nerve in the adiposetissue, the nerve affecting urinary function, and at least oneexpandable anchoring structure deployable from the lead to engage theadipose tissue and resist dislodgment and/or migration of the lead andelectrode within the adipose tissue, the expandable anchoring structuresized and configured to form an open structure that enlarges in diameterfrom distal to proximal to resist proximal passage of the lead andelectrode through the adipose tissue, placing the expandable anchoringstructure in a collapsed condition, implanting the electricallyconductive portion and the expandable anchoring structure in the adiposetissue, expanding the anchoring structure into the adipose tissue toresist dislodgment and/or migration of the electrically conductiveportion within the adipose tissue, tunneling a proximal portion of thestimulation electrode assembly to an anterior pelvic region remote fromthe at least one electrode, providing an implantable pulse generatorsized and configured to be positioned in subcutaneous tissue in theanterior pelvic region remote from the at least one electrode, couplingthe implantable pulse generator to the stimulation electrode assembly,implanting the implantable pulse generator in the anterior pelvic regionremote from the at least one electrode, and operating the implantablepulse generator to convey electrical stimulation waveforms through thestimulation electrode assembly to achieve selective stimulation of thenerve to affect urinary function.
 19. A method according to claim 18further including providing a sleeve having an interior bore sized andconfigured to create percutaneous access to the adipose tissue.
 20. Amethod according to claim 18 wherein the pulse generator includes alarger end and a smaller end allowing for positioning the smaller end inthe subcutaneous tissue first, and positioning the larger end in thesubcutaneous tissue last.
 21. A method according to claim 18 wherein thenerve comprises a left and/or right branch of the dorsal genital nerve.22. A method comprising providing a system to affect urinary functionaccording to claim 13, selecting within the adipose tissue the adiposetissue region at or near a pubic symphysis innervated by a nerveaffecting urinary function, implanting the stimulation electrodeassembly in the adipose tissue region, and conveying electricalstimulation waveforms through the stimulation electrode assembly toachieve selective stimulation of at least one nerve innervating theadipose tissue region.
 23. A method according to claim 22 wherein thestimulation stimulates a left and/or right branch of the dorsal genitalnerves to treat urinary incontinence.
 24. A method according to claim 22wherein the stimulation bilaterally stimulates both the left branch andthe right branch of the dorsal genital nerve to treat urinaryincontinence.
 25. A system to affect urinary function, the systemcomprising: a stimulation electrode assembly, the assembly comprising anelongated lead, the lead including an electrically conductive portion,the electrically conductive portion sized and configured to be implantedin an adipose tissue region at or near a pubic symphysis innervated by anerve affecting urinary function, and to apply electrical stimulation tothe nerve in the adipose tissue region affecting urinary function, anexternal pulse generator sized and configured to be worn by a patient,the external pulse generator comprising a removable and replaceableelectronics pod, the electronics pod comprising circuitry adapted togenerate electrical stimulation current patterns to be delivered throughthe lead and to the electrically conductive portion, the electronics podalso comprising a power input bay adapted to receive a disposable powersource that can be released and replaced for a prescription period, andinstructions for use prescribing the release and replacement of thepower source according to a prescribed power source replacement regime,the prescribed power source replacement regime comprising thereplacement of the power source on a prescribed repeated basis similarto administering a pill under a prescribed pill-based medication regime.